...FORBES ROBERTSON Abstract Knoop indentation hardness numbers may be obtained on polished mineral grains as small as 10 microns in diameter. This paper gives average Knoop numbers for 127 opaque minerals and quartz. The limits of tests and the average hardness number are plotted on a logarithmic...

...A. A. Giardini Abstract The directional hardness of single crystal silicon has been investigated both by a method of peripheral grinding on oriented thin circular specimens and by Knoop micro-indentations. Grinding hardness has been evaluated in the principal zones [100], [110] and [111]. Knoop...

...Horace Winchell Abstract The Tukon testing machine with a Knoop indenter has useful possibilities in the measurement of hardness of mineral specimens. Not only does the instrument afford numerical hardness values such as argentite = 25, calcite = 100, fluorite = 150, magnetite = 700, corundum...

... linear relationship was obtained when the logarithm of Mohs' hardness number was plotted against the Vickers' microhardness value. This allowed a recomputation of Mohs' numbers which established that the numbers are far from arbitrary and are spaced in a reasonably systematic manner, except possibly...

...D. K. Paul; S. S. Saha Abstract The Knoop indentation hardness number of dolomite (dolostone) increases with increase in Ca and Mg. GeoRef, Copyright 2008, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society...

... investigated scratch hardness of the Mohs minerals, and reported a logarithmic trend of Mohs number with scratch hardness. Experimental techniques for the indentation of brittle materials were further developed in the 20 th century. For example, Knoop et al. (1939) described a pyramidal diamond indenter...

... hardness values that are different according to the measurement technique used, which is commonly attributed to (1) indenter geometries (Knoop, Vickers, or Berkovich); (2) applied loads; (3) time at the maximum load; and (4) number of indentations. However, in this case, major effects are related...

.... The Vickers and Knoop average values range from 132 to 140 kg/mm 2 in good accordance with the 135 kg/mm 2 value given by Hodgman (1961) as the Knoop value for calcite. There are just a limited number of significant correlations between the various parameters ( Table 6 ). Absolute density (G...

... may be observed. In obtaining indentations only those specimens are used which under the microscope show little or no sand. Thus the indentation number associated with a certain depth in a given well represents the aggregate hardness of a relatively sand-free sample of shale. Indentation numbers...

... that Mineral Identification is pitched as a practical guide for amateur mineralogists, some of the included material seems superfluous. For example, a table (p. 16, entirely repeated on p. 197) compares the Mohs hardness scale and VHN 100 and Knoop hardness scales, when at most a simple plot of Mohs versus...

... that LP204-1 magnetite grains have a Vickers hardness of 604 ± 19 kg/mm 2 (and a comparable Knoop hardness) whereas 90LP9 magnetite grains have a hardness of 544 ± 27 kg/mm 2 . The Vickers (and Knoop) hardness of 94AK3 was intermediate between those of 90LP9 and LP204-1 at 579 ± 23 kg/mm 2 . We attribute...

... systems through use of first-order reversal curve diagrams Rev. Geophys. 52 557 602 Robertson, 1961 Robertson F. 1961 Knoop hardness numbers for 127 opaque minerals Geol. Soc. Am. Bull. 72 621 637 Solari et al., 2004 Solari L.A. Keppie J.D. Ortega-Gutiérrez F...

... performance has materially deteriorated. The higher animals need besides its trophon, its caloric food, a great number of ergones. It is quite probable that for the five functional groups mentioned, a large part of the substances needed are synthesised, and provided for, by plants. So, for groups K the B...

... and after exposure ( I after – I before ). Note significant loss of intensity at bond angles less than 140°. Microhardness tests of silica showed that both the crack initiation load and the Knoop hardness were constant with time in a dry non-aqueous environment, but decreased...

... by salt mist 14157 Determination of abrasion resistance 14158:2004 Determination of rupture energy 14205:2003 Determination of Knoop hardness D5873-05 Determination of rock hardness by rebound hammer method 14579:2004 Determination of sound speed propagation 14580:2005...

... of high-pressure mineral physics studies with the Kawai-type apparatus at SPring-8, some of which are already being realized at the present HPES beamline. The hardness of the anvil materials imposes constraints on the attainable pressures in high-pressure apparatus. The Knoop hardness of tungsten...

... with grain sizes of 10 30 71 nm have been reported to have Knoop hardness values as high as 110 140 GPa. A 72 nanotwinned diamond (nt diamond) with an average twin thickness of 5 8 nm, 73 which was synthesized by compressing onion-structured precursors, was recently 74 reported to possess a Vickers hardness...

... and P i ‾ is a recorded pilot signal trace after complex conjugation. The length of each trace before the Fourier transform is 30 s. The number of traces N k used to produce a single trace at depth level k depends on a drilling rate of penetration (ROP) and a selected drilling depth...

... and 1924), of protein (Knoop, Oesterlin, Chibnall), 108 and of the great number of other classes of substances. Glucose may be broken down by all, or nearly all organisms (see Section 7.1, The Concept of Symbiosis and Antagonism ). It is rarely present in the outer milieu, as it is such a universal...

...” (Spanish for “cloak” or “blanket”) replacement bodies in the limestone with sulfide mineralized veinlets in the hanging-wall shales and sandstones. In many areas these shales are metamorphosed to hard, compact pyritic hornfels. Mantos consist of massive fine- to coarse-grained pyrite, pyrrhotite, galena...